1. Field of the Invention
The present invention relates to a temperature determining device that detects the temperature of a determination object member on the basis of the intensity of infrared rays. Furthermore, this invention relates to a temperature correcting method for use in determining temperature using an infrared temperature detecting unit. Moreover, this invention relates to an image forming apparatus that includes a temperature detecting unit for use in image forming apparatuses employing electrophotography and electrostatic recording that detects the temperature of a fixing member for fixing an unfixed image on the basis of the intensity of infrared rays from the fixing member.
2. Description of Related Art
JP2002-228523 A discloses a temperature calculating method using an infrared temperature detector. This temperature calculating method is illustrated in FIG. 11. As shown in the figure, in Procedure 1, an environmental temperature Tamb is calculated using a themistor output Vntc of a thermistor provided on a cold junction member of a thermopile. Then, in Procedure 2, a correction coefficient A is calculated using the environmental temperature Tamb. After that, in Procedure 3, temperature is calculated using the environmental temperature Tamb, the correction coefficient A, and a thermopile output Vout.
Furthermore, JP2001-34109 A discloses the use of an infrared temperature sensor in an image forming apparatus.
However, the above-mentioned temperature calculating method disclosed in JP2002-228523 A has presented the following problem.
That is, according to this method, in determining temperature, infrared rays that are radiated from peripheral members of a determination object member and then are reflected from a surface of the object member also are considered as infrared rays radiated from the object member. Therefore, even when the temperature of the object member is constant, the determined temperature may change due to a change in the temperature of the peripheral members. Conversely, if temperature control is performed with respect to the object member on the basis of the determined temperature thus obtained, the temperature of the object member may vary considerably.